The present invention relates to a two-port valve which can be easily maintained and is used as a high vacuum L valve or the like.
As shown in FIG. 18, a two-port valve used as the high vacuum L valve or the like is conventionally well known.
The well-known two-port valve has a valve body 111 which includes ports 112 and 113 formed in an orthogonal direction, a valve seat 114 provided in a flow path connecting these ports 112 and 113 to each other, and an open end 115 facing the valve seat 114. A cylinder 120 of a pneumatic cylinder system 119 which drives a valve element 123 is formed in a bonnet 117 which is airtight attached to the open end 115 through a bellows plate 116.
A valve rod 124 of the valve element 123 which opens and closes the valve seat 114 airtight penetrates the bonnet 117 and is connected to a piston 121 of the pneumatic cylinder 119, and a return spring 125 is compressed between the valve element 123 and the bonnet 117. Further, the bonnet 117 is provided with a port 127 which supplies and discharges compressed air to and from a bellows plate 116-side pressure chamber 126 which is defined by the piston 121.
The both ends of a bellows 128 which surrounds the valve rod 124 are airtight, fixedly attached to the inner peripheral surface of the bellows plate 116 and to the valve element 123, and annular attachment grooves 130 for respectively attaching seal rings 131 are formed on the surface of the valve element 123 on which the valve element 123 faces the valve seat 114.
However, the well-known two-port valve has the following problem. It is necessary to detach the bonnet 117 from the valve body 111 so as to exchange the seal ring 131 of the valve element 123 or to wash the bellows 128 or the inner surface of the valve body 111. Since the bonnet 117 is fixedly attached to the valve body 111 by bolts (not shown), it is necessary to loosen the bolts to detach the bonnet from the valve body 111. However, since the bonnet 117 cannot be easily attached and detached to and from the valve body 111, it takes time to do maintenance.
The present invention has been made to solve such a problem and its technical object is to provide a two-port valve capable of easily dissembling and assembling a valve body and a bonnet and making maintenance easy.
It is another technical object of the present invention to provide a safe two-port valve capable of preventing a bonnet from being detached from a valve body by an erroneous operation while having a structure of enabling simple dissemble.
To solve the problem, a maintenance-easy two-port valve according to the present invention comprises: a valve body including two ports, a valve seat in a flow path connecting the two ports to each other, and an open end; a valve member opening and closing the valve; a bonnet airtight connected to the open end of the valve body, and containing a cylinder system driving the valve member; and a connection mechanism for detachably connecting the bonnet to the valve body, and is characterized in that the connection mechanism comprises: a plurality of shafts attached to the valve body, penetrating the bonnet in an axial direction, and each having a tip end protruding outward from an outer end face of the bonnet; a handle attached onto the outer end face of the bonnet to be rotatable around an axis and displaceable in the axial direction, and having one or a plurality of engagement pins on a surface facing the outer end face of the bonnet; a plate provided between the bonnet and the handle to be rotatable around the axis, and including a plurality of engagement grooves engaged with or disengaged from upper ends of the shafts, respectively, and one or a plurality of engagement holes into which or from which the one or plurality of engagement pins are fitted or disengaged, respectively; and a spring disposed between the handle and the plate, and urging the handle and the plate in a direction in which the handle and the plate are away from each other and a direction in which the handle and the plate are rotated relative to each other.
According to the present invention, the two-port valve is constituted so that the bonnet includes a lock pin engaged with and disengaged from the plate, and the lock pin is stopped at the plate to lock the plate to the bonnet if the plate is at a position at which the plate is engaged with the shafts and a position at which the plate is disengaged from the shafts, and the lock pin is detached from the plate to release locking of the plate to the bonnet while the plate is rotated from the position at which the plate is engaged with the shafts to the position at which the plate is disengaged from the shafts.
According to the present invention, the two-port valve is further constituted so that the handle includes a plurality of elliptic grooves, the upper ends of the shafts being displaceably fitted into the elliptic grooves, respectively, a push-down position of the handle is specified when an end wall on one longitudinal side of each of the elliptic grooves is abutted on each of the shafts, and a position at which the shafts are disengaged from the engagement grooves of the plate, respectively, is specified when an end wall on the other side of each of the elliptic grooves is abutted on each of the shafts, and constituted so that the plate includes one or a plurality of elliptic holes, a bolt fixed to the bonnet being displaceably fitted into each of the elliptic holes, a position at which the shafts are engaged with the engagement grooves of the plate, respectively is specified when an end wall on one longitudinal side of each of the elliptic holes is abutted on the bolt, and a position at which the shafts are disengaged from the engagement grooves of the plate, respectively is specified when an end wall on the other side of each of the elliptic holes is abutted on the bolt.
According to another aspect of the present invention, the cylinder system includes a piston actuated by a function of fluid pressure; and a valve rod penetrating the bonnet to extend into the valve body, and connecting the piston to the valve member, and a return spring urging the valve member in a valve opening direction and a bellows surrounding the valve rod and the return spring are provided between the bonnet and the valve member.
Furthermore, according to the present invention, the two-port valve is constituted so that a counter rotation prevention pin is provided at the handle, a hole, into which the counter rotation prevention pin is displaceable fitted, is provided in the plate, and so that the counter rotation prevention pin is constituted to be stopped in the hole and to prevent the handle from being rotated in a counter direction when the bonnet is connected to the valve body.
According to the maintenance-easy two-port valve, even if the handle is to be pushed down at the rotation position other than the push-down rotation position, the push-down prevention pin is abutted on the plate and the handle cannot be, therefore, pushed down. However, if the handle is rotated to the push-down rotation position, the position of the push-down prevention pin coincides with the position of the engagement hole provided in the plate. It is, therefore, possible to push down the handle and to engage the push-down prevention pin with the engagement hole.
If the handle is rotated in this state, the plate can be rotated to the position at which the engagement groove thereof is detached from the retaining groove of each shaft since the plate is engaged with the handle by the push-down prevention pin. If the handle is lifted at this position, the bonnet connected to the handle can be detached from the valve body.
Furthermore, if the bonnet is inserted into the valve body and the handle is rotated to the push-down rotation position and pushed down, then the push-down prevention pin can be engaged with the engagement hole. If the handle is rotated in this state, the plate can be rotated to the position at which the engagement groove thereof is engaged with the retaining groove of each shaft. It is, therefore, possible to attach the bonnet to the valve body.
As can be seen, since the maintenance-easy two-port valve is constituted so that the bonnet can be attached to or detached from the valve body only by pushing down, rotating and lifting the handle, the valve body and the bonnet can be easily disassembled and assembled.